Boom rigging



E. B. NICKLES BOOM RIGGING Jan. 8, 1963 3 Sheets-Sheet 1 Filed Oct. 28,1960 'EN TOR.

Edvard B. Mckles Jan. 8, 1963 E. B. NICKLES 3, 7

BOOM meme Filed on. 28, 1960 3 Sheets-Sheet 2 IN VEN TOR.

Edvard B. Mz'kZea BY HTTO E Y Jan. 8, 1963 E. B. NICKLES 3, 7

BOOM RIGGING Filed Oct. 28, 1960 I 3 Sheets-Sheet 3 INV EN TOR.

ATTOEV BfiZZZfiS Patented Jan. 8, 1963 Free 333723265 poor r RlGGlNGEdward B. Nickles, Manitowoe, Wis, assignor to Manitowoc EngineeringCorporation, Manitowoc, Wis. a corporation of Wisconsin Filed st. 23,19%, Ser. No. 65,801 16 Claims. {Cl. 212-59) The invention relates toboom rigging and more particularly to an auxiliary suspending orsupporting rigging assembly utilized in conjunction with a conventionalboom structure and rigging in such manner as to limit the amount ofdownward bow in the boom structure thereby increasing the load-carryingcapacity thereof.

The use of relatively long booms is becoming more and more commonplaceand, as well, the actual lengths employed are being steadily increased.For example, it is not now unusual to encounter operations where boomshaving lengths exceeding 250 feet are desirable as well as practical.The utilization of such booms possess problems not realized with themuch shorter booms which, in the past, were used almost exclusively. Onesuch problem stems from the fact that the weight of a long boom becomesa material factor in the stresses which the boom must undergo duringuse. Consequently, the load-carrying capacity of the boom is reduced.The limiting factor is not the substantially pure compressive stressesinduced when the boom is at or near a vertical position where its weightis acting axially therealong but the limiting factor is the stressesinduced by bending when the boom is disposed near a horizontal position.When horizontal, the weight of the boom will be acting entirely as abending moment, tending to produce a downward bowing or deflection ofthe boom. Of course, this deflection imposes a severe limitation uponthe load-carrying capacity of the boom since further loading of theboom, conventionally rigged, by imposition of a load thereon will onlyincrease the deflection.

In other words, the weight of a conventionally rigged boom having alength such as is common today will produce suflicient downward bow ofthe boom when horizontally disposed as to seriously impair or limit theadditional loading which may be imposed on the boom. This occurs byreason of the fact that long booms especially are susceptible to failureby buckling initiated by bowing. That is to say, a boom such as iscontemplated here is acting as a long, thin column and, as is wellknown, such members fail most easily due to excessive bowing orbuckling.

it is therefore a primary object of the present invention tocontroliably limit the boom-weight induced bowing or deflection of aboom so as to thereby increase the loadcarrying capacity of the boom.

it is also an object of this invention to provide an auxiliary supportassembly, cooperable with a conventional pendant bridle support as usedfor raising and lowering a boom, which will limit the downward bow of aboom.

A further object of this invention resides in the provision of anauxiliary rigging assembly for supporting a boom which cooperates with aconventional pendant bridle type support structure in such manner as tolimit the downward bow of the boom to a predetermined maximum when theboom is disposed substantially horizontal, that is, in the most adverseposition of loading, and which will automatically decrease its eliect asthe boom is moved toward the vertical, so that as the boom approachesthe condition in which the forces acting thereon are substantiallyentirely axial compressive forces, the natural deflection or bow of theboom then being at a minimum, the effect of the auxiliary support willalso be at a minimum.

A still further object of the present invention is to provide anauxiliary rigging assembly for supporting booms which is so arrangedgeometrically relative to the boom and the support therefor as toproduce a maximum supporting force when the boom is disposed generallyhorizontal and which produces a progressively lessening supporting forceas the boom is moved toward the vertical.

It is also a further object of this invention to provide improved boomsupport structure for supporting a hingeably mounted boom wherein theboom support structure includes a conventional bridle pendant riggingand an elongated bodily flexible element which is anchored at one endportion to a location which is adjacent the boor hinge and at the otherend portion to the boom at a location thereon which is intermediate theend portions thereof with the elongated element being supportedintermediate the end portions thereof from the pendant bridle supportstructure.

An additional object of this invention is to provide an improved boomsupport structure for supporting a boom which is hingeably mounted tothe upper works of a crane, or the like, wherein the boom supportstructure includes pendant bridles which extend generally longitudinallyalong the boom from the upper works to the boom point and an auxiliaryassembly in the form of an elongated bodily flexible cable which has oneend portion anchored at a location on the upper works which is withinthe angle defined by the boom and the pendant bridles with the cableextending away from the location and passing over a sheave, pulley, orthe like, which is carried by the pendant bridles with the other endportion of the cable being secured to the boom at a location thereonwhich is intermediate the end portions thereof.

In order to accomplish the desired objects as stated above, the improvedboom support structure for supporting a boom which may be hingeablymounted to the upper works of a crane, or the like, comprises anauxiliary boom support assembly in the form of an elongated bodilyflexible rope or cable which cooperates with the conventional type ofpendant bridles which are employed for supporting the boom and forenabling the boom to be raised and lowered as desired. The bodilyflexible elongated cable is anchored to the upper works of the crane ata location thereon which is within the confines of an angle that isdefined by the boom and the pendant bridle support structure and thecable extends away from the stated location on the upper works andpasses over a sheave or pulley which is secured to and carried by thependant bridle support structure and the other end portion of the cableis anchored and secured to the boom at a location thereon which isintermediate the hinge and the boom point.

Other objects, advantages and important features of the invention willbe apparent from a study of the specification following, taken with thedrawing, which together describe, disclose and illustrate an embodimentof the invention and what is now considered and believed to be the bestmode of practicing the principles thereof. Still other embodiments maybe suggested to those having the benefit of the teachings herein, andsuch other embodiments are intended to be reserved especially as theyfall within the scope and breadth of the subjoined claims.

In the drawing:

FIGURE 1 is a side elevational view of a crane apparatus having aconventional boom and rigging and illustrating an auxiliary supportstructure according to this invention incorporated therewith;

FIGURE 2 is a diagrammatic view of the crane apparatus of FIG. 1 showingthe boom disposed substantially horizontal and illustrating in fulllines the boom having the auxiliary support structure applied theretoaovaaee and in dotted lines the boom without the auxiliary supportstructure;

FIGURES 3, 4 and 5 are each diagrammatic views similar to H6. 2 butillustrating, in each instance, the boom as being disposed in variousdifferent positions relative to the horizontal;

FlGURE 6 is a diagrammatic View showing the geometrical relationship ofthe auxiliary support structure with an associated boom;

FIGURES 7 and 8 are force diagrams illustrating a boom as being disposedhorizontally and partially ele vated, respectively, and showing thevariations in the force components acting on a boom and a pendant bridlesupport structure therefor as the boom is raised while supporting agiven load; and

FIGURES 9 and 10 are force diagrams showing the bending moment effectproduced by the Weight of the boom and illustrating the variationstherein as the boom is raised.

Attention is now directed to FIG. 1 of the drawing wherein there isillustrated a crane 10 having an elongated boom 12 hingeably connectedto an upper works 14 by a hinge structure 16 with the boom 12 extendingtherefrom and terminating in a boom point 18.

According to conventional practice, the boom 12 may comprise a pluralityof insert sections 20 each of which includes a plurality of chords 21and interconnecting reinforcing lacing members 25, all preferably formedfrom tubular steel stock, although it will be appreciated that othermaterials may be used and that insofar as the present invention isconcerned the specific construction of the boom 12 may be in any desiredfashion or manner and further that it is the relationship of the boom 12and the support structure therefor, as will be hereinafter set forth.which is significant and important in connection with this invention.

A gantry 24 is pivotally mounted to the upper works 14 and carries ananchor strap and a back hitch strap 28. A back hitch pendant extendsbetween the gantry 24 and the upper works 14 for maintaining the gantry2.4 in a position, as illustrated, which enables the boom 12 to beoperated as desired and the anchor strap 26 enables the gantry 24 to betied to the upper works 14 to position the gantry 24 in a loweredposition. The back hitch strap 28 carries sheaves 32 which cooperatewith a sprea er or equalizer assembly 34 having sheaves 3638 thereon byreason of a boom hoist rope 4% which is wound upon a boom hoist 42 andissues therefrom to pass first over the sheave 38 of the spreaderassembly 34 then over the gantry sheave 32, back to the spreader sheave36 and finally back to an anchor 44 on the back hitch strap 28.

A load hoist cable 36 is provided which is Wound about a hoist drum 48and passes through guides 50 to sheaves 52 secured adjacent the boompoint 18 and the load hoist cable 46 then passes on to any load L beinghandled by the crane l0.

Boom rigging or boom support structure 54 is provided for supporting theboom 12 during the operation thereof on movement between a substantiallyhorizontal position to a substantially vertical position as illustratedin FIGS. 35. The support structure 54 includes primary support structure56 defined by a plurality of elongated bodily flexible pendant bridles,such as cables, ropes, or the like, which are interconnected inend-to-end fashion by connectors 58 with the interconnected pendantbridles 56 extending between the spreader or equalizer assembly 34 andthe boom point 1% with the adjacent end portions of the pendant bridlesupport structure 56 being anchored respectively thereto. The pendantbridles are each preferably made in sections of suitable lengths whichsubstantially correspond to the length of the insert sections 20 of theboom 12 which enables the overall effective length of the boom 12 andthe pendant bridle support structure 56 to be adjusted and varied fordifferent conditions by merely adding or removing the in ert sections 20together with the corresponding associated pendant bridles 56.

The boom rigging 54 further includes auxiliary sup port structure 60 inthe form of an assembly including a bodily flexible elongated member 62which may also be preferably a cable or a rope having a fixed unstressedlength.

An anchor device 64 secures one end portion of the member 62 to theupper Works 14 at a location thereon which is within the confines of anangle A defined by the boom 32 and the pendant bridle support structure56 with the location being intermediate the boom 12 and the back hitchstrap 28. As illustrated in FIG. 1 of the drawing the anchor device 64comprises an upstanding stand as having a pivotally mounted arm 68 whichextends generally in the direction toward the apex of the angle A.

Another anchor device 7% secures the other end portion of the member 62at a suitable location 72 along the boom i2 with the location '72 beingintermediate and spaced from the hinge structure 16 and the boom point18 of the boom 12. In actual practice, it has been found preferable toposition the location 72 as near as possible to the center of the boom12, i.e., somewhere adiacent to the mid point between the hingestructure lo and the boom point 18.

The member 62 is secured to the arm 68 and extends therefrom above theadjacent portion of the boom 12 be tween the boom 12 and the pendantbridle support structure 56 toward the boom point 1.8 or the apex of theangle A and passes over or through a support 7 in the form of anantifriction device 75, such as a sheave, pulley, or the like, carriedby the connector 58 of pendant bridle support structure which isdisposed adjacent to the location 72. on the boom 12 so that theintermediate portion the member 62 is flexibly supported by the sheavedevice through the pendant bridle support structure 56.

In order to provide the member 62 with a desired amount of tension, anadjustment 76, in the form of a turnbuckle, or the like, may be providedand, as iilustrated, such adjustment is shown as being disposedadjace...-. to the arm 68 of the anchor device For the sake of brevity,in the above description and disclosure, only one element of therespective support structures and associated accessories has beenmentioned, but it is to be noted and understood that correspondingelements and accessories are provided in laterally spaced relationshiprelati've to each other on one side of the crane l0 and the boom 12.

It is also to be understood that other apparatus than the crane it; maybe provided with the improved boom rigging support structure of thisinvention and in such instances the auxiliary rigging assembly as willbe an chored to a base from which the boom 12 may be pivoted in themanner as described and disclosed above with refereuce to the upperworlts of the crane it}.

The effect of the auxiliary support assembly as on th: boom 12 may benoted from an inspection of H63. 2- wherein there is illustrated, insolid lines, the boom is having the auxiliary support assembly asprovided therewith while in dotted lines a boom H2 is illustrated, forthe purpose of comparison, which is not provided with the auxiliarysupport assembly 64 it is to be noted that the boom 112 has anappreciable amount of normal downward bow or natural deflection due tothe weight of the boom while the boom l2, which is provided with theauxiliary support assembly 60, has a controlled bow or downwarddeflection which is materially reduced. In actual practice, it has beenfound that the resulting effect of employing the auxiliary supportassembly as with the boom 12 will decrease the normal downward bow ornatural deflection therein by a value equal to at least one half theextent of the normal downward bow or natural deflection.

As can be seen sequentially in FIGS. 25, as the boom is raised towardthe vertical, less and less deflection or bow results. The reason forthis is twofold. First, the bending moment exerted on the boom by virtueof its weight W decreases progressively as the boom is moved fromhorizontal toward the vertical since the moment arm is progressivelydecreased. Second, the axial coinpressive force component in the boom astransmitted thereto by the pendant bridle support structure 56 decreasesfrom the horizontal toward the vertical position of the boom.

This latter effect can be seen more clearly in FIGS. 7 and 8 of thedrawing. In FIG. 7, the boom is substan tially horizontal and the load Lis equal to the boom weight component at the free end of the boom pluswhatever actual load is being supported. In order to support the boomunder this condition, the pendant bridle support structure must exert aforce R-l which produces a vertical component R-3 equal to the load L.An axial compression force R-Z is imposed upon the boom which is ofcourse opposed at the hinged connec tion for the boom. Consider now FIG.8 wherein the same load L is supported by the boom which is now at about45 elevation. In FIG. 8, due to the changed geometry of the forcesystem, the pendant bridle support structure must exert a much smallerforce R-4 to produce the vertical component R-3 which is equal to theload L. Likewise, the axial compression component R-S on the boom ismuch smaller than the compression component R-Z. Thus, it will beappreciated that as the boom is raised, with the load L remainingconstant, both the tension in the pedant bridle support structure andthe axial compression component in the boom decrease progressively.Theoretically, the tension in the pendant bridle support structure wouldbe zero when the boom is prefectly vertical and the axial compressioncomponent in the boom would be equal to the load L.

To consider the effect produced by the weight W of the boom, referenceis now had to FIGS. 9 and 10 of the drawing. In FIG. 9, the boom issubstantially horizontal and the weight W thereof acts through thecenter of gravity at a moment arm M1 effecting forces at the hingestructure 16 to produce a bowing effect. When, on the other hand, theboom is raised from the horizontal, as in FIG. 10, the moment arm M-Z ismuch smaller thus producing considerably less bowing or deflection inthe boom.

it will be appreciated, however, that the bowing etiect is not producedsolely by the weight of the boom but is also effected by the axialcompression force on the boom. Therefore, when the boom is horizontaland y the bending moment due to the weight of the boom and the axialcompression force is greatest, the maximum deflection will occur.Conversely, since both the bending moment and the axial compressionlessen as the boom is raised, the deflection is correspondinglydecreased. Therefore, to utilize the principle of the present invention,some provision should be made to decrease the auxiliary supportingefiect as the boom is raised, for if such is not done, the relativelylarge auxiliary support effect necessary when the boom is horizontal maywell produce a reversal of the deflection at some point during theraising of the boom.

The manner in which the auxiliary support force is decreased as the boomis raised is illustrated in FIG. 6. In this FIGURE, the boom 12 isillustrated in full lines in the horizontal position and in dotted linesin a partially raised position. In the horizontal position, theauxiliary support cable member 62 is illustrated by a--b and in theraised position by cd. For the sake of simplicity, the auxiliary supportportion b is illustrated as of the same length and parallel to thepartial length X of the boom 12. when the boom is horizontal. Althoughthis condition need not prevail for proper operation of this invention,the principle involved is the same in any case.

As stated, in FIG. 6, a plus x and of course a plus b equal the fixedlength of the auxiliary support cable member 62. Now, when the boom 12is raised through angle Z, as shown, it can be seen by inspection that dis approximately equal to x minus y although due to the fact that d isnot parallel to the boom 12, it will be slightly greater than x minusbut not significantly so. In any event, it is easily seen that d is lessthan both x and b. Consequently, 0 must be greater than a. Therefore,the force exterted by the auxiliary support member 62 decreases as theboom 12 is raised since the distance a and c in FIG. 6 reflect theamount of deflection imparted to the pendant bridle support structure 56by the auxiliary support assembly 6% see also FIGS. 2-5. In other words,the force exerted by the auxiliary support assembly at} is caused by thedegree to which the pendant bridle support structure 55 isdeflected fromits otherwise substantially straight line condition, coupled with theamount of tension in the pendant bridle support structure 56. Since thetension in the pendant bridle support structure 56 steadily decreases asthe boom 12 is raised it is not necessary that the deviation from thestraight line of the pendant bridle support structure 56 be decreased asthe boom 12 is raised in order to decrease the auxiliary supportassembly 60 force. In fact, in FIGS. 2-5, the deflection of the pendantbridle support structure remains substantially constant and in thiscase, it is substantially solely the decrease in the pendant bridlesupport structure 56 tension which decreases the auxiliary supportassembly 64 force as the boom is raised. However, this deflection of thependant bridle support structure 56 is of course dependent upon thegeometry involved and may be altered as desired.

While the invention has been described and disclosed in terms of anembodiment which it has assumed in practice, the scope of the inventionshould not be deemed to be limited by the precise embodiment hereinshown, illustrated, described and disclosed and it is to be understoodthat other such embodiments are intended to be reserved, especially asthey fall within the scope of the claims herein subjoined.

I claim as my invention:

1. In a crane having an upper works, an elongated boom hingeably mountedto the upper Works and bodily flexible pendant bridle support structurefor supporting the boom, the improvement comprising, in combination withthe boom, the upper works and the pendant bridle support structure, anauxiliary support assembly including an elongated bodily flexiblemember, a device for anchoring one end portion of said member to theupper works of the crane at a location thereon which is within theconfines of an angle defined by the boom and the bodily flexible pendantbridle support structure, another device for anchoring the other endportion of the member to the boom at a location thereon which isintermediate the end portions thereof, and still another device forsupporting the intermediate portion of the member from the bodilyflexible pendant bridle support structure.

2. In a crane having an upper works, an elongated boom hingedly mountedto the upper works and bodily flexible pendant bridle support structurefor supporting the boom, the improvement comprising, in combination withthe boom, the upper works and the pendant bridle support structure, anauxiliary support assembly including an elongated bodily flexiblemember, a device for securing one end portion of said member to theupper works of the crane, another device for securing the other endportion of the member to the boom at a location thereon which isintermediate the end portions thereof, and still another device forsupporting the intermediate portion of the member from the bodilyflexible pendant bridle support structure.

3. A crane having an upper works, an elongated boom hingeably mounted tothe upper works, bodily flexible pendant bridle support structure forsupporting the boom, and an auxiliary support assembly including anelongated bodily flexible cable-like member, a device for securing oneend portion of said member to the upper works of the crane at a locationthereon which is within the confines of an angle defined by the boom andthe bodily flexible pendant bridle support structure, another device forsecuring the other end portion of the member to the boom at a locationthereon which is intermediate the end portions thereof, and ananti-friction device for supporting the intermediate portion of themember from the bodily flexible pendant bridle support structure.

4-. Support structure for supporting an elongated hingeably mounted boomfrom a base, said support structure including a plurality of pairs ofelongated cable devices attached to and extending between the base andthe boom, one of said cable devices of each pair having the intermediateportion thereof supported from the other cable device of the respectivepair.

5. T he support structure as set forth in claim 4 wherein each of saidone cable devices has one endportion there of anchored to the base andthe other end portion thereof anchored to the boom at a location thereonwhich intermediate the end portions thereof.

6. Support structure for supporting an elongated hii ably mounted boomfrom a base, said support structure including a pair of elongatedmembers attached to and extending between the base and the boom, one ofsaid members having the intermediate portion thereof su ported from theother member.

7. The support structure as set forth in c" n 6 whcrc in said one memberhas one end portion chored to the base and the other end portion thereofanchored to the boom at a location thereon which is intermediate the endportions thereof.

8. In combination with a boom hingeably mounted to a base and primarysupport structure for supporting the boom during movement thereofbetween generally horizontally disposed and generally verticallydisposed positions, auxiliary su rort structu -e to suppo ting the boom,said auxiliary support structure including an elongated bodily flexiblemember, a device for securing one end portion of the member to the base,a other device for securing the oth r end portion of the to interediateportion or the boom, and still another device for supporting anintermediate portion of the member from the primary support structure.

In combination with a boom hin eably mounted to a base and primarysupport structure for supporting the boom during movement thereof,auxiliary support structure for supporting said boom, said auxiliarysupport structure including an elongated bodily flexible member havingone end portion anchored to the base and the other portion anchored toan intermediate portion of the boom, and ant iction device for flexiblysupporting an intermediate portion of the member the primary supportstructure.

it). In combination with a boom hingeably mounted to a base and primarysupport structure for supporting the boom during movement thereof,auxiliary sup-port structure for supporting the boom, said auxiliarysupport structure including an elongated bodily flexible member havingone end portion anchored to the base and the other end portion anchoredto an termediate portion of the boom, and a device for supporting anintermediate portion of the member from the primary support structure.

11. An elongated boom hingeably mounted to an upper Works of a crane,said boom extending away from said upper works and terminating in a boompoint, support structure extending between the upper Works and the boompoint, said support structure defining With said boom an angle,auxiliary support structure extending between the upper works and theboom, said auxiliary support structure including a bodily flexibleelongated cable-like memer, a device securing one end portion of themember to the upper Works at a location thereon which is Within theconfines of the angle defined by the support structure and the boom,another device securing the other end portion of the member to the boomat a location thereon which is intermediate the end portions thereof,and still another device supporting an intermediate portion of themember from the support structure.

12. An elongated boom hingeably mounted to a base, said boom extendingfrom said base and terminating in a boom point, primary supportstructure extending between the base and the boom point, said primarysupport structure defining With said boom point an angle, auxiliarysupport structure extending between the base and the boom, saidauxiliary support structure being supported by the primary supportstructure and secured to the base at a location thereon which is withinthe confines of the angle defined by the support structure and the boomand secured to the boom at a location thereon which is intermediate theend portions thereof.

13. An elongated boom hingeably mounted to a base, elongated primary andauxiliary support structure extending between the base and the boom forsupporting the boom from the base, said auxiliary support structurebeing supported intermediate the end portions thereof by the primarysupport structure and secured adjacent one end portion to the base andalso secured adjacent the other end portion to the boom at a locationthereon which is intermediate the end portions thereof.

14. A support assembly for supporting a boom having one end portionhingeably mounted to a base, said as sembly including a device foranchoring one end portion of member to the base adjacent the hinged endportion or the boom, another device for anchoring the other end port onof the member to an intermediate portion of the boom, and flexiblesupport structure for supporting an intermediate portion of the memberfrom the base.

15. A support assembly for supporting a boom having one end portionhingeably mounted to a base, said assembly including an elongated bodilyflexible member having one end portion secured to the base adjacent thehinged end portion of the boom and the other end portion thereof securedto an intermediate portion of the boom, and apparatus for flexiblysupporting an intermediate por tion of the member from the base.

l6. A support assembly for supporting a boom having one end portionhingeably mounted to a base, said assembly including a device foranchoring one end portion of a member to the base, another device foranchoring the other end portion of the member to an intermediate portionof the boom, and anti-friction support structure for flexibly supportingan intermediate portion of the member from the base.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A CRANE HAVING AN UPPER WORKS, AN ELONGATED BOOM HINGEABLY MOUNTEDTO THE UPPER WORKS AND BODILY FLEXIBLE PENDANT BRIDLE SUPORT STRUCTUREFOR SUPPORTING THE BOOM, THE IMPROVEMENT COMPRISING, IN COMBINATION WITHTHE BOOM, THE UPPER WORKS AND THE PENDANT BRIDLE SUPPORT STRUCTURE, ANAUXILIARY SUPPORT ASSEMBLY INCLUDING AN ELONGATED BODILY FLEXIBLEMEMBER, A DEVICE FOR ANCHORING ONE END PORTION OF SAID MEMBER TO THEUPPER WORKS OF THE CRANE AT A LOCATION THEREON WHICH IS WITHIN THECONFINES OF AN ANGLE DEFINED BY THE BOOM AND THE BODILY FLEXIBLE PENDANTBRIDLE SUPPORT STRUCTURE, ANOTHER DEVICE FOR ANCHORING THE OTHER ENDPORTION OF THE MEMBER TO THE BOOM AT A LOCATION THERON WHICH ISINTERMEDIATE THE END PORTIONS THEREOF, AND STILL ANOTHER DEVICE FORSUPPORTING THE INTERMEDIATE PORTION OF THE MEMBER FROM THE BODILYFLEXIBLE PENDANT BRIDLE SUPPORT STRUCTURE.